1. Field of the Invention
The present invention relates to a method, apparatus, and system for controlling an imaging apparatus which is adapted to be controlled via a network so that a desired video signal is generated by the imaging apparatus and is distributed over the network, and also to a recording medium storing a program according to which the method, apparatus, and system are implemented or operated.
2. Description of the Related Art
It is known in the art of the imaging system to connect a video camera to a network such as the Internet and transmit a video signal obtained via the video camera over the network so that the video signal can be observed at various remote locations. In some such systems, users can observe not only an image taken via a video camera but also can remotely control the conditions of the video camera such as the panning and tilting angle and the zooming ratio via the network. For example, there is a system in which a video camera that can be computer-controlled is connected to a WWW (World Wide Web) server on the Internet so that an image taken by the video camera is distributed on a real-time basis to clients via the network wherein the clients are allowed to control the video camera.
In such a system in which a plurality of clients are allowed to access the computer-controllable video camera at the same time, an image signal sensed by the video camera can be transmitted to the plurality of the clients at the same time and thus the plurality of clients can view the image. However, it is impossible for a plurality of clients to control the video camera at the same time. In the conventional systems, no priority in terms of the control of the video camera is given to any client, and clients operate the video camera under no particular control. Therefore, if a plurality of clients issue, at the same time, camera control commands requesting that the video camera be tilted or panned into different angles, the camera control system interprets and executes the camera control commands in the order of reception. As a result, continual competition occurs among clients to attempt to control the video camera. If such competition occurs, no clients can control the video camera and the image taken by the video camera in such a situation will be meaningless to any client.
One known technique of avoiding the above problem is to give permission to control the video camera for a fixed period of time to one client after another. However, in this technique, each client can control the video camera only for a limited period of time and thus it is difficult for clients to control the video camera in a desired manner.
In view of the above, it is an object of the present invention to provide a method, apparatus, and system for performing image sensing operations in an efficient manner in response to video data transmission requests or video camera control requests issued by a plurality of clients.
It is another object of the present invention to provide a storage medium storing a program implementing such a method.
It is still another object of the present invention to provide a method, apparatus, and system capable of avoiding competition among a plurality of clients in access to imaging apparatus so that the imaging apparatus may be controlled correctly in response to requests of the respective clients. It is a further object of the present invention to provide a storage medium storing a program implementing such a method.
According to an aspect of the present invention, to achieve at least one of the above objects, there is provided a control apparatus for controlling a plurality of camera servers, each camera server comprising a video camera and a controller for controlling the video camera. The control apparatus comprises: receiving means for receiving a control command transmitted from a client; interpreting means for interpreting the control command received via the receiving means; and selecting means for selecting a camera server in a free state from the plurality of camera servers when the interpreting means determines that the control command is a video camera control permission request.
According to another aspect of the present invention, there is provided a camera control system for making connections via a network among (1) a plurality of camera servers each including a video camera and a controller for controlling the video camera, (2) a control apparatus for controlling the plurality of camera servers, and (3) clients. The control apparatus comprises: receiving means for receiving a control command transmitted from a client; interpreting means for interpreting the control command received via the receiving means; and selecting means for selecting a camera server in a free state from the plurality of camera servers when the interpreting means determines that the control command is a video camera control permission request; and wherein each camera server comprises controlling means for controlling the video camera in accordance with a control command given by the client when the camera server is selected by the selecting means.
According to still another aspect of the present invention, there is provided a controlling method of a control apparatus for controlling a plurality of camera servers each including a video camera and a controller for controlling the video camera, the controlling method comprising the steps of: receiving a control command output by a client; interpreting the control command received in the receiving step; and if in the interpreting step the command is interpreted as a video camera control permission request, selecting a camera server in a free state from the plurality of camera servers.
According to a further aspect of the present invention, there is provided a controlling method of a camera control system for making connections via a network among (1) a plurality of camera servers, (2) a control apparatus for controlling the plurality of camera servers, and (3) clients. The method comprises the steps of: receiving a control command output by a client; interpreting the control command received in the receiving step; if in the interpreting step the command is interpreted as a video camera control permission request, selecting a camera server in a free state from the plurality of camera servers; and if a camera server is selected in the selecting step, controlling the video camera in accordance with a control command received from the client.
According to another aspect of the present invention, there is provided a storage medium for storing a program in accordance with which a control apparatus performs a process for controlling a plurality of camera servers each including a video camera and a controller for controlling the video camera, the process comprising the steps of: receiving a control command output by a client; interpreting the received control command; and if in the interpreting step the command is interpreted as a video camera control permission request, selecting a camera server in a free state from the plurality of camera servers.
These and other objects and features of the present invention will become more apparent from the following detailed description and the accompanying drawings.